Fusion with space related aspects thread

[josh_simonson]

<p>Here's an interesting lecture at google last week about a different means of achieving fusion than the typical tokamak. This work was recently declassified when the navy's long horizon energy research programs were cut (of which this was one). Interestingly, they transfered the lab equipment to SpaceDev where it's being babysat while alternative funding is being arranged. Near the end Bussard talks about applications as a space engine.</p><p><a name="Video">[/url]http://video.google.com/videoplay?docid=1996321846673788606 </p><p><a title="Google video" target="_blank" href=" <a href="http://video.google.com/googleplayer.swf?docId=1996321846673788606" target="_blank">http://video.google.com/googleplayer.swf?docId=1996321846673788606</a>"> [/url] </p><p><font size="-1">Google Tech Talks November 9, 2006
</font>
<font size="-1"> ABSTRACT This is not your father's fusion reactor! Forget everything you know about conventional <span class="invisible" /><span class="visible">thinking on nuclear fusion: high-temperature plasmas, steam turbines, neutron radiation and even nuclear waste are a thing of the past. Goodbye thermonuclear fusion; hello inertial electrostatic confinement fusion (IEC), an old idea that's been made new. While the international community debates the fate of the politically-turmoiled $12 billion ITER (an experimental thermonuclear reactor), simple IEC reactors are being built as high-school science fair projects.

Dr. Robert Bussard, former Asst. Director of the Atomic Energy Commission and founder of Energy Matter Conversion Corporation (EMC2), has spent 17 years perfecting IEC, a fusion process that converts hydrogen and boron directly into electricity producing helium as the only waste product. Most of this work was funded by the Department of Defense, the details of which have been under seal... until now.

 Dr. Bussard will discuss his recent results and details of this potentially world-altering technology, whose conception dates back as far as 1924, and even includes a reactor design by Philo T. Farnsworth (inventor of the scanning television).

Can a 100 MW fusion reactor be built for less than Google's annual electricity bill? Come see what's possible when you think outside the thermonuclear box and ignore the herd.</span></font></p>

[TyMoore]

Inertial Electrostatic Fusion and the Farnsworth "Star" Fusor have actually been used for decades in the form of small portable neutron generators. The bursts of fusion neutrons are actually generated in a vacuum tube loaded with a small amount of deuterium and tritium gas. The Fusor lies at the center and the electrostatic grid is charged to some thousands of volts positive to accelerate the positive ions toward the geometric center--as the ions oscilate through the center, some of them collide with sufficient energy to fuse.

See:

http://www.farnovision.com/chronicles/fusion/vassilatos.html

A nice description on how to actually build one of these devices is available at:

http://www.belljar.net/634fusor.pdf

Here is a nice piece on the Farnsworth Fusor:

http://fti.neep.wisc.edu/iec/AmericanScientist.htm

The device can produce powerful bursts of neutron radiation useful for downhole detection petroleum deposits in the oil business and in certain kinds of biological imaging, but the amount of fusion going on is measurable in terms of picowatts to microwatts.  It cannot produce much more than--and in any case, such devices are extremely dangerous because of the penetrating nature of the neutrons.  Full body neutron exposure can be quickly fatal, and with a machine that can produce KiloHertz bursts of 10^9 to 10^10 energetic neutrons each burst (this translates to a neutron fluence of 10^18 to 10^19 neutrons per second!) Still, such devices do not scale up millions of times well, and cannot produce millions or billions of watts needed for something like a powerplant. It is interesting physics, but it is not a power generating machine....

[meiza]

Could these devices store antimatter too instead of magnetic confinement?

[TyMoore]

Not very much and not efficiently--because the particles would tend to oscillate through the center the probability is very high that they will eventually collide with the accelerating grid. Because one cannot physically make an infinitely thin accelerator grid, then dissipative losses will prevent long confinement times. This is one of the reasons why inertial confinement fusion is limited to small scales, and why a similar device cannot be used to store antimatter. The only way around that limitation is to create a 'virtual' cathode--but that requires application of some really tricky physics that deal with radio-frequency induction, ion cyclotron heating, and these resonances are not the same as the ion resonances exhibited by the IEC Fusor... so you end up with a completely different device anyway...

[josh_simonson]

These guys are using the same principle of electrostatic confinement, but a much different means to go about it than Farnsworth.  Watch the video, it's quite interesting.

[PurduesUSAFguy]

I guess the main question in my mind is how do you convert the reaction in an IE containment fusion device into useable power? It seems like engineering a pressurized water loop through such a device would be difficult and I don't think you could use MHD coupling with Boron-Hydrogen fusion, although I don't really know...

It's an interesting concept, and I hope it works, but so many have worked so long on fusion that I tend to be very skeptical of anyone who has 'figured it out' outside of the established plasma physics community.

That being said I do think that the answer to commercially viable fusion is something 'out of the box' and that ITER isn't the road to fusion power. I think we need to focus more on novel devices like Princeton’s near spherical tokomak and basic plasma physics.

[mong']

What I am wondering is: how difficult is it to build a fusion rocket (i.e: that is supposed to leak some plasma out the back) compared to an electricity producing reactor ?
it would seem that a thruster would be easier because you don't have to worry about producing more power than you need, no complex energy conversion mechanisms and since you want to eject some of plasma the leakage problems are somewhat mitigated.
whadya think ?

[meiza]

You still need to transfer the energy to a working fluid... Unless you use it as a in-space drive where high thrust is not necessary.

[mong']

yes that's what I am talking about, an in space propulsion system, low thrust/very high ISP expelling only the charged fusion products throuh a magnetic nozzle.
although it would be a good idea to increase thrust with a working fluid, even if it decreased the ISP significantly, it would still be very interesting

[Marcus]

PurduesUSAFguy - 19/11/2006  1:42 PM

I guess the main question in my mind is how do you convert the reaction in an IE containment fusion device into useable power? It seems like engineering a pressurized water loop through such a device would be difficult and I don't think you could use MHD coupling with Boron-Hydrogen fusion, although I don't really know...

Way back in my early undergrad years I was working with a professor who did some of the more out there propulsion research at Purdue. It was the guy who's concentrated-Hydrogen-Peroxide-soaked cabinets set his room in the ASL on fire in the 2000 time-frame (that was an exciting day at the lab, let me tell you)

Along with his real research, he engaged us Aero and Nuke undergrads in our pie-in-the-sky theoretical research projects (read: fantasies). The one I was working on was a spacecraft powered by a pair of IEC's using direct energy conversion to siphon off about 5-10% of the power from each reactor. We were trying to scale up a small propulsive effect observed when some conducting geometries were energized using 50,000 volt capacitors. It turned out that we were just seeing an ion wind effect due to our inability to pull a good vacuume in our leaky bell jars. Anyway, the point was that the Nukes were convinced that they would be pulling Megawatt-type power from a 3mX3m self-sustaining IEC box using 5-10% efficient direct energy conversion. No indirects or anything (because we didn't have room for the thermal cycle stuff onboard our spacecraft.) This miraculous breakthrough was, at the time, 10 years away. Which, today, would make it--in the nature of all fusion applications--about 10 years away. :p :p

Haha, I remember working on the airframe for the "spacecraft". Initially it started out looking like the teardrop-shaped silver thing from "Flight of the Navigator" thanks to the propulsion system, but the radiator surface necessary for the IEC's kept growing until we started referring to it as "Hell's Butterfly." We thought we'd be launching from the ground, but considering the massive voltages we were working with, I think it would have been more likely to find gainful use as more of a giant bug-zapper than an actual spacecraft. Maybe we could've convinced the Japanese they needed it to kill Mothera or something.

[PurduesUSAFguy]

That's pretty cool Marcus,

Speaking of Purdue I'm just glad Armstrong hall is about to Open, Aero E has needed a better building then Grissom Hall for a long time now...

[Marcus]

PurduesUSAFguy - 20/11/2006  12:53 PM

Speaking of Purdue I'm just glad Armstrong hall is about to Open, Aero E has needed a better building then Grissom Hall for a long time now...

I dunno. I sort of liked the distinction of being the best students in the worst building. Well, I guess the old art school qonset huts were worse, but Aeros are still better.

When is Armstrong hall opening, and who is going to be in there? I'll be back for Xmas and I'd like to check it out. I was thinking about going for back for a MS in about 2 years, either Aero or Nuke. It'd be cool if they put the Nukes and Aeros together. After all, Aero/Astros have more in common with Nukes than they do with IEs, and the ME's already have their own building. Then again, I enjoyed raiding the IE's clubs' meetings for pizza and then retreating back to the Aero lounge.

[PurduesUSAFguy]

Well Armstrong Hall was supposed to be AAEs only but last year they switched from Hall of AAE to Hall of Engineering...I heard that they might be putting the soon to be established nano-tech program in there with us.../shrug/.

It wouldn't shock me if a couple nuke classes didn't find there way into there as well as Nuke is kind of stuck in the corner behind the engineering mall behind the Tech building.

I think its supposed to open first semester of next year, but it looks pretty close to done right now.

[Marcus]

As long as they bring their reactor with them. *Fiendish laugh*  
Ya know, all 1 kW of it.
Yeah, I had to go back there to talk to a prof about my senior project. That's what got me interested, actually. If you don't mind me asking, do you work at Purdue, or student?

[PurduesUSAFguy]

Student, double major in AAE and Nuke-E actually...although one of those might turn into Physics.